Various types of support arm assemblies are used in holding up the lids of top opening structures. Representative examples of such structures are described in U.S. Pat. Nos. 406,595; 1,096,964; 1,303,441; 1,986,307; 2,587,200; 4,925,223; and 5,570,493. These patents can be generally divided into two groups, as described in more detail below.
The first group involves designs wherein a generally linear brace member is pivotally mounted to the lid of a top opening structure with its opposite end slidably mounted to the base of the structure via a connecting member engaged in a linear slotted element running parallel to a side edge of the structure. As the lid opens, the connecting member slides along the slotted element towards the hinges joining the lid and base. Likewise, when the lid is closed, the connecting member slides along the slotted element away from the hinges joining the lid and base. Thus, U.S. Pat. No. 406,595 discloses a trunk support arm or brace that is pivotally mounted to the lid with its opposite end slidably mounted via a member engaging a slot formed parallel to the side edge of the trunk opening. U.S. Pat. No. 1,096,964 likewise has a brace pivotally mounted to the lid with the opposite end of the brace being slidably mounted via a member engaged in a slot formed parallel to the side edge of the trunk opening. However, in this patent the slot faces the lid rather than the interior of the trunk (as in U.S. Pat. No. 406,595). The slot also has a shoulder allowing the brace to be temporarily affixed in an upright position. U.S. Pat. No. 1,986,307 teaches a variation wherein the slot can be mounted on the lid as well as on the base with the brace being pivotally mounted to the base rather than the lid. In this patent recesses or hooks formed in the slot allow the member sliding in the slot to catch at different points, thereby allowing the separation between the base and lid to be set at different distances. Similar designs can be seen in U.S. Pat. Nos. 2,587,200; 4,925,223; and 6,292,978.
The second group of patents involves designs wherein a generally linear support arm or brace member is pivotally mounted to the lid of a top opening structure with its opposite end sliding through a slot or opening in a bracket affixed to the side edge of the structure's base. In these designs, the brace generally remains transverse to the slot or opening as the top is opened or closed. In the first group of designs, the brace is generally parallel to the slotted element when the top is closed and moves into a more-or-less transverse position when the top is open. U.S. Pat. Nos. 1,303,441 and 5,570,493 provide examples of designs from the second group. In these patents, a brace member is pivotally mounted to the lid of a top opening structure. Its opposite end slides through, and is transverse to, a slot in a bracket-type member affixed to the side edge of the base. A pin/peg in the opposite end cooperates with a hook/groove included in or adjacent to the bracket-type member, allowing the lid to be affixed in an upright or open position. However, even thought the number of pieces and the general construction of the devices included in the second group is simpler and less expensive than those in the first group, there remains a need for support arm assemblies that are simple, sturdy, and suitable for use with the types of heavy, durable fire-resistant storage containers manufactured by our company.
The bodies and lids of our company's fire-resistant storage containers, also referred to as fire-resistant safes, are constructed by joining internal and external shells together so that they form a mold that can be filled with insulation material 10a, 10b as best seen in FIGS. 2 and 3. (The insulation material 10a, 10b itself is generally a concrete mixture that solidifies in the mold formed by the internal and external shells.) Understandably, the lid and the body of our safes, like those of most safes, are relatively heavy. Thus, it is necessary that any support arm assembly used in holding the lid of the safe in an open position be sturdy as well as being easily released and compact. In addition, it is desirable that the components of the assembly be simple to use and manufacture, that the assembly be easy to put together, and that the assembly by easy to affix to the interior of the safe's body and lid. All of these factors promote customer convenience and/or minimize the time and expense necessary for manufacture. These requirements are not fully met by any of the prior art assemblies known to us.